1. Field of the Invention
The present invention relates to coaxial cable connectors and more particularly, to such a coaxial cable for connecting a coaxial cable to a mating device, for example, cable TV signal line, maintaining excellent signal transmission.
2. Description of the Related Art
U.S. Pat. No. 8,011,955, invented by the present inventor and now allowed for patent, discloses a coaxial cable connector for assembly with one of a series of coaxial cables having one same specification and different wire outer diameters that uses a plastic bushing for compressing by a barrel to wrap about the coaxial cable and compress an inner tube against the aluminum foil and insulation spacer of the coaxial cable, protecting the coaxial cable against weather and extending the lifespan. A short distance is left between the aluminum foil insertion hole on the left end of the inner tube and the left orifice of the barrel, facilitating insertion of the insulation spacer and aluminum foil of the coaxial cable without causing damage.
A coaxial cable connector is adapted for connecting a coaxial cable B to a mating device 8. As shown in FIG. 2, the mating device 8 comprises a base member 81, an F-connector 82 forwardly extended from the front side of the base member 81. The F-connector 82 is externally threaded, having a front contact face 83 and a metal clamp 84 disposed on the inside.
Before fastening up the screw nut 1 of the aforesaid prior art coaxial cable connector with the outer threads of the F-connector 82 of the mating device 8, as shown in FIG. 1 (equivalent to FIG. 9 in the specification of the prior art patent), the face 1a of the screw nut 1 is kept apart from the stop face 2a of the inner tube 2. The face 1a of the screw nut 1 can be kept in positive contact with the stop face 2a of the inner tube 2 for grounding only after the screw nut 1 and the F-connector 82 of the mating device 8 have been fastened up tightly. If the screw nut 1 is not fastened tight after installation, or the screw nut 1 is loosed after a long use, noise interference may occur during signal transmission.
To avoid this problem, an improved commercial coaxial cable connector design is known. According to this design, as shown in FIG. 3, a spring plate 90 is set in between the screw nut 91 and inner tube 92 and the main body tube 93. As shown in FIG. 3A, the spring plate 90 is retained between the inner tube 92 and the main body tube 93 and kept in contact with the screw nut 91. Thus, either the screw nut 91 is fastened tight or not, the inner tube 92, the main body tube 93 and the screw nut 91 provide a grounding function. However, the structural arrangement has the drawbacks of high installation cost, low spring force and instable contact. Further, the installation of the spring plate 90 is limited to a particular direction. Further, this spring plate 90 is specially designed, its fabrication cost is high.